A hydraulic breaker according to the present invention is installed on construction equipment, such as excavators, and extensively used for breaking rocks, concrete, etc. When a piston moves down in a cylinder due to fluid pressure, the piston strikes an upper portion of a chisel serving as an excavating tool, so that the chisel breaks the rocks or concrete.
FIG. 1 is a perspective view showing a hydraulic breaker according to the related art, and FIG. 2 is an exploded perspective view showing main components of the hydraulic breaker according to the related art.
In general, as shown in FIGS. 1 and 2, the hydraulic breaker includes a back head 210 provided therein with a gas chamber therein; a cylinder 220 assembled to a lower portion of the back head 210; a front head 230 assembled to a lower portion of the cylinder 220; a piston 240 moving up and down in the cylinder; and a chisel 250 installed in the front head 230.
The gas chamber provided in the back head 210 is filled with gas. When the piston 240 moves up in the cylinder 220, the gas in the gas chamber is compressed. When the piston 240 moves down, the compressed gas pushes an upper portion of the piston 240.
In addition, a valve and an accumulator are installed outside the cylinder 220 provided therein with the piston 240. As the valve operates, fluid pressure is supplied. If the fluid pressure is not supplied through the valve due to the rapid operation, the accumulator is operated to properly supply the fluid pressure.
The chisel 250 is installed in the front head 230 assembled to the lower portion of the cylinder 220. As the piston 240 strikes the chisel 250 while moving down in the cylinder 220, the chisel 250 breaks the rocks or concrete.
Meanwhile, according to the hydraulic breaker 200 of the related art shown in FIGS. 1 and 2, in order to assemble the back head 210, the cylinder 220 and the front head 230 with each other, perforation holes 211 and 221 are formed at each corner of the back head 210 and the cylinder 220, fastening holes 231 are formed at each corner of an upper surface of the front head 230, and nut assembling grooves 231 are formed below each fastening hole 231 of the front head 230 such that lower nuts 262 can be fastened in the nut assembling grooves 231.
According to the hydraulic breaker 200 of the related art, after the cylinder 220 and the back head 210 have been placed on the front head 230, a fastening bolt 260 is inserted into the fastening hole 231 of the front head 230 by passing through the perforation hole 211 of the back head 210 and the perforation hole 221 of the cylinder 220. Then, an upper nut 261 and the lower nut 261 are fastened to upper and lower ends of the fastening bolt 260.
That is, according to the hydraulic breaker 200 of the related art, when the back head 210, the cylinder 220 and the front head 230 are assembled with each other, the lower nut 262, which is specifically designed, is fastened to the lower end of the fastening bolt 260 inserted into the front head 230 by passing through the back head 210 and the cylinder 220. Then, the fastening bolt 260 is fastened by a torque wrench from the top of the back head 210. However, since the length of the fastening bolt 260, which is specifically designed to assemble the back head 210, the cylinder 220 and the front head 230 with each other, is too long, the fastening bolt 260 may be fastened in a state that the fastening bolt 260 is biased. In this case, when the construction work is performed by installing the hydraulic breaker 200 on an excavator, the biased fastening bolt 260 may return to its initial position as vibration is applied thereto, so tension of the fastening bolt 260 may be released. Thus, it is necessary to fasten again the upper nut 261 and the lower nut 262.
If the construction work continues without fastening the upper and lower nuts 261 and 262 due to the carelessness or the lack of common sense for construction equipment, the striking force of the chisel 250 may be degraded, the fastening bolt 260 may be broken, and main components of the cylinder 220 may be damaged.